Design and implementation of robust visual servoing control of an inverted pendulum with an FPGA-based image co-processor

This paper presents the design and implementation of robust real-time visual servoing control with an FPGA-based image co-processor for a rotary inverted pendulum. The position of the pendulum is measured with a machine vision system. The pendulum used in the proposed system is much shorter than those used in published vision-based pendulum control system studies, which makes the system more difficult to control. The image processing algorithms of the machine vision system are pipelined and implemented on a field programmable gate array (FPGA) device to meet real-time constraints. To enhance robustness to model uncertainty and to attenuate disturbance and sensor noise, the design of the stabilizing controller is formulated as a problem of the mixed H2/H∞ control, which is then solved using the linear matrix inequality (LMI) approach. The designed control law is implemented on a digital signal processor (DSP). The effectiveness of the controller and the FPGA-based image co-processor is verified through simulation and experimental studies. The experimental results show that the designed system can robustly control an inverted pendulum in real-time.